Your immune system is designed to protect your body from harmful invaders,such as bacteria. Sometimes, however, the system responds to substances normally considered harmless. The substance that provokes the attack is called an allergen; the substances that attack the allergen are called antibodies.
A food allergy can provoke such a response as your body releases antibodies to attack specific proteins in food. When this happens, some of the physical reactions include
✓ Hives
✓ Itching
✓ Swelling of the face, tongue, lips, eyelids, hands, and feet
✓ Rashes
✓ Headaches, migraines
✓ Nausea and/or vomiting
✓ Diarrhea, sometimes bloody
✓ Sneezing, coughing
✓ Asthma
✓ Breathing difficulties caused by tightening (swelling) of tissues in the throat
✓ Loss of consciousness (from anaphylactic shock)
If you’re sensitive to a specific food, you may not have to eat the food to have the reaction. For example, people sensitive to peanuts may break out in hives just from touching a peanut or peanut butter and may suffer a potentially fatal reaction after simply tasting chocolate that has touched factory machinery that previously touched peanuts. People sensitive to seafood — fin fish and shellfish — have been known to develop breathing problems after simply inhaling the vapors or steam produced by cooking the fish.
Understanding how an allergic reaction occurs
When you eat a food containing a protein to which you’re sensitive, your immune system releases antibodies that hitch a ride on white blood cells called basophils. The basophils circulate through your entire body, giving the antibodies the chance to hop off and bind to immune system cells called mast cells.
Basophils and mast cells produce, store, and release histamine, a natural body chemical that causes the symptoms — itching, swelling, hives — associated with allergic reactions. Yes, that’s why some allergy pills are called antihistamines. When the antibodies carried by the basophils and mast cells come in contact with food allergens, boom! You have an allergic reaction.
Investigating two kinds of allergic reactions
Your body may react to an allergen in one of two ways — immediately or later on:
✓ Immediate reactions are more dangerous because they involve a fast swelling of tissue, sometimes within seconds after contact with the offending food.
✓ Delayed reactions, which may occur as long as 24 to 48 hours after you’ve been exposed to the offending food, are usually much milder, perhaps a slight cough or nasal congestion caused by swollen tissues.
Most allergic reactions to food are unpleasant but essentially mild. However, as many as 150 to 200 people die every year in the United States from a severe reaction to a food allergy.
Call 911 immediately if you — or a friend or relative — show any signs of an allergic reaction — including an allergic reaction to food — that affects breathing.
It’s all in the family: Inheriting food allergies
A tendency toward allergies (although not the particular allergy itself) is inherited. If one of your parents has a food allergy, your risk of having the same problem is two times higher than if neither of your parents were allergic to foods. If both your mother and your father have food allergies, your risk is four times higher
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